Damaging components with defective electrical couplings

ABSTRACT

A method, in some embodiments, comprises: providing a component having first and second electrical nodes; determining that the component lacks multiple, functional electrical couplings between said first and second nodes; damaging at least part of the component as a result of said determination; and determining, as a result of said damage, that the component is defective.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of the earlier U.S.Utility Patent Application to Truhitte entitled “Damaging Componentswith Defective Electrical Couplings,” application Ser. No. 15/240,835,filed Aug. 18, 2016, now pending, the disclosure of which is herebyincorporated entirely herein by reference.

BACKGROUND

Semiconductor components, such as packages that contain integratedcircuits or discrete devices, perform one or more functions in thecontext of a larger electronic system within which they are deployed.Often, such components will contain multiple electrical couplingsbetween a pair of nodes. For example, a package may contain multiplewire bonds coupling a pin (e.g., terminal or lead on the lead frame) toa common point (e.g., a bond pad) on a die. If the functional integrityof one or more of these electrical couplings is compromised, the packagemay not be able to perform properly. Identifying and removingcompromised packages and other components from the assembly line,however, remains a challenge.

SUMMARY

At least some of the embodiments disclosed herein are directed to amethod, comprising: providing a component having first and secondelectrical nodes; determining that the component lacks multiple,functional electrical couplings between said first and second nodes;damaging at least part of the component as a result of saiddetermination; and determining, as a result of said damage, that thecomponent is defective. One or more of these embodiments may besupplemented using one or more of the following concepts, in any orderand in any combination: wherein said damaging comprises using a laser toshort one or more electrical connections in the component; wherein saiddamaging comprises using a laser to open one or more electricalconnections in the component; wherein using the laser to open the one ormore electrical connections comprises opening an electrical couplingbetween the first and second nodes; wherein said electrical couplingbetween the first and second nodes is selected from the group consistingof: wire bonds, clip bonds and ribbon bonds; wherein said damagingcomprises dispensing an electrically conductive material to short one ormore electrical connections in the component; wherein said damagingcomprises electrically coupling a top surface of a die to a bottomsurface of the die; wherein said damaging comprises electricallycoupling a top or bottom surface of a die to a side surface of the die;wherein said damaging comprises using an electrostatic discharge;further comprising performing said damage using a wire bonding machine;wherein determining that the component is defective comprisesdetermining that the component is defective during an electrical test.

At least some embodiments are directed to a method, comprising:providing a component having multiple electrical nodes; identifying adefect in an electrical coupling scheme between said multiple nodes; andintroducing electrical damage to the component upon identifying saiddefect. One or more of these embodiments may be supplemented using oneor more of the following concepts, in any order and in any combination:wherein said component is selected from the group consisting of: anintegrated circuit package, a discrete device package, a multi-diedevice, a multi-chip module, a system in package, and a passive device;wherein said component comprises a diode or a transistor; wherein saidmultiple nodes include a component terminal and the surface of a die;wherein said electrical coupling scheme includes one or more electricalcouplings between the multiple nodes; wherein introducing saidelectrical damage comprises applying laser light to the component ordispensing electrically conductive material into the component; whereinintroducing said electrical damage comprises electrically coupling twoseparate surfaces of a die in said component; wherein introducing saidelectrical damage comprises introducing an electrical parametric defectto said component; further comprising performing an electrical testafter introducing said electrical damage; determining, as a result ofsaid electrical test, that said component is defective; and as a resultof said determination, removing said component from an assembly line.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side view of a discrete device package.

FIG. 2 is a top-down view of a discrete device package.

FIGS. 3A-5 are top-down views and/or side views of discrete devicepackages being damaged using a laser.

FIGS. 6-8 are top-down views of discrete device packages being damagedby dispensing electrically conductive material.

FIG. 9 is a side view of an integrated circuit package.

FIG. 10 is a top-down view of an integrated circuit package beingdamaged using a laser.

FIG. 11 is a top-down view of an integrated circuit package beingdamaged by dispensing electrically conductive material.

FIG. 12 is a flow diagram of a method for damaging components withdefective or missing electrical couplings.

It should be understood that the specific embodiments given in thedrawings and detailed description thereto do not limit the disclosure.On the contrary, they provide the foundation for one of ordinary skillto discern the alternative forms, equivalents, and modifications thatare encompassed together with one or more of the given embodiments inthe scope of the appended claims.

DETAILED DESCRIPTION

Disclosed herein are techniques for identifying and intentionallydamaging semiconductor components that carry a risk of failure orimproper operation due to defects, such as defective or missingelectrical couplings between common nodes within the components. (Theterm “component,” as used herein, includes—without limitation—completedsemiconductor packages, multi-die devices, multi-chip modules, systemsin packages, passive devices, and any such packages, devices, and/ormodules that are in the assembly process.) The techniques describedherein may more broadly be applied to any component that is defective inany way. Defective components—such as those that have missing ordefective electrical couplings between a pair of nodes within thecomponent—are identified using a suitable detection system, such as awire bond detection system or a vision system. Damage is subsequentlyinflicted on the defective components using any suitable technique—forinstance, by creating electrical shorts or opens using, e.g., lasers,electrically conductive material, electrostatic discharges or hydrogenflames. This damage causes the defective components to malfunctionduring electrical tests at the end of the manufacturing process, and,consequently, the damaged components are removed from the assembly line.The following figures and description frequently refer to packages—and,more particularly, to discrete device packages—but the varioustechniques described herein may be applied to any and all types ofcomponents, and the following figures and description should not beconstrued as a limitation on the scope of the disclosure.

FIG. 1 is a side view of a discrete device package 100 that includesmultiple leads 102, 104. A die 106 is mounted on the lead 102 using asuitable die bond material 108 (e.g., a conductive material, such assolder or an epoxy). The bottom surface of the die 106 electricallycouples to the lead 102 via the die bond material 108. The top surfaceof the die 106 electrically couples to the lead 104 via electricalcouplings (e.g., wire bonds, clip bonds, ribbon bonds) 110, 112. The topand bottom surfaces of the die 106 are electrically isolated from eachother. The package 100 additionally includes a mold 114. In thisconfiguration, the die 106 may function as a discrete device such as adiode or a transistor, although the scope of disclosure is not limitedto any particular type of component or configuration of leads, die andelectrical couplings. To function properly, the package 100 requiresthat multiple, functional electrical couplings connect the top surfaceof the die 106 to the lead 104. (The term “functional electricalcouplings,” as used herein, means electrical couplings that formelectrical pathways in the manner required for proper operation of thepackage.) The electrical couplings 110, 112 fulfill this requirement, asthey maintain structural integrity and are properly coupled to the die106 and the lead 104. FIG. 2 is an illustrative, top-down view of thediscrete device package 100 of FIG. 1. As in FIG. 1, the package 100shown in FIG. 2 has multiple, functional electrical couplings 110, 112that enable the package to operate as intended. The electrical couplingsconnect the top surface of the die 106 to the lead 104. The scope ofdisclosure is not limited to packages or other components that requiremultiple, functional electrical couplings between die and leads. Rather,the disclosure encompasses components requiring multiple, functionalelectrical couplings between any set of nodes (i.e., two or more nodes)within the component—for instance, between a die and another die,between two leads or terminals, and the like.

Not all such components, however, have the required number offunctional, properly-connected electrical couplings. For example, insome cases one or more of the required electrical couplings may beomitted or one or more of the electrical couplings may be damaged ordefective in some way. FIG. 3A is an illustrative, top-down view of apackage 300 missing an electrical coupling that is required for thepackage to operate properly. Specifically, the package 300 includes adie 302 coupled to a lead 304 via an electrically conductive die bond(e.g., a conductive epoxy; not expressly shown), and it further couplesto a lead 306 using only one electrical coupling (e.g., wire bond, clipbond, ribbon bond) 308. However, it is missing an additional electricalcoupling between the top surface of the die 302 and the lead 306. Thus,because the package 300 lacks the additional electrical coupling, thepackage 300 cannot operate as intended. Such a defective package mayescape detection during an end-of-assembly electrical test, but it wouldlikely fail during implementation in the field. The defective electricalcoupling scheme can, however, be detected during assembly using a wirebond detection system and/or a vision system, both of which are known inthe art.

After a component with a defective electrical coupling scheme (e.g.,missing one or more required functional, electrical couplings betweentwo or more nodes) is detected, the component is physically damaged byany suitable technique—for instance, by introducing an electrical short,an electrical open, or both. Accordingly, FIG. 3A depicts a laser cut310 that introduces an electrical short to a package. The laser cut 310is made using any suitable laser source, such as an ALLTEC® or ROFIN®laser, with an illustrative wavelength of 1.064 micrometers. The lasercut 310 is applied across the die 302, cutting through the entirethickness of the die. (Alternatively, the laser cuts through just theactive surface of the die 302.) The heat generated by the laser causesmetallic traces on the die and/or semiconductor material within the dieto melt and flow, thus forming an electrically conductive pathwaybetween the top surface of the die 302, the die bond, the lead 304 andthe bottom surface of the die 302. This electrically conductive pathwayforms an electrical short, thus damaging the die 302 and rendering itfunctionally unacceptable and/or altogether inoperable.

FIG. 3B is a partial, magnified side view of the package 300 after thelaser cuts through the full thickness of the die 302. As shown, the heatfrom the laser cut 310 results in a melting and flow of electricallyconductive materials, including the die 302, metallic components on thedie, and the die bond material 312. This melt-and-flow process formselectrically conductive pathways 314 between the top surface of the die302 and the lead 304, which, in turn, is already electrically connectedto the bottom surface of the die 302. Additionally, the top surface ofthe die 302 couples to the die bond material 312. In this way, anelectrical short has been formed. This electrical short will berecognized as a defect during electrical testing, and the package willbe picked from the assembly line and discarded. Laser cuts such as thatdepicted in FIG. 3A are not limited to any particular shape, size, depthor pattern. Any and all types of damage that can be inflicted by a laserare contemplated and included within the scope of this disclosure.

FIGS. 4 and 5 show alternate locations at which the laser cut 310 may bemade. Specifically, FIG. 4 shows a laser cut 310 applied on theelectrical coupling 308. This laser cut severs the electrical coupling308, leaving no electrical connection between the die 302 and the lead306 (i.e., an electrical open). While a single electrical couplingbetween the die 302 and the lead 306 may not be detected as a defectduring electrical testing, the absence of any electrical couplingbetween the die 302 and the lead 306 will be detected as a defect.Accordingly, the package will be removed from the assembly process. FIG.5 shows a laser cut 310 applied on both the die 302 (which can be a cutthrough the full thickness of the die or just through the top, activesurface of the die) and the electrical coupling 308. This results in asevered electrical coupling 308 (i.e., an electrical open), as describedwith respect to FIG. 4. In addition, in the event of a cut through thefull thickness of the die, it may result in a melt-and-flow processbetween the multiple surfaces of the die 302, the die bond materialunder the die 302, and the lead 304 (i.e., an electrical short), asdescribed with respect to FIGS. 3A and 3B. For example, electricallyconductive material molten by the laser cut may flow from the topsurface of the die 302 to one or more sides of the die 302, to thebottom surface of the die 302, to the die bond, and/or to one or moresurfaces of the lead 304. As explained, such defects will be detectedduring end-of-assembly electrical testing and will cause the package tobe removed from the assembly process.

As previously explained, techniques other than laser cutting may be usedto inflict damage on defective components. FIGS. 6-8 depict top-downviews of a package 300 that is defective due to an insufficient numberof functional electrical couplings between the top surface of the die302 and the lead 306 and that has been electrically shorted by thedispensation of electrically conductive material as a result. Suchelectrically conductive material may include any fluid (i.e., capable offlowing, regardless of viscosity) metals or alloys—for instance,solder—that may be dispensed in any desired quantity or form tointroduce one or more electrical shorts into the package 300. FIG. 6,for instance, depicts electrically conductive material 316 that has beendispensed over the electrical coupling 308 and over at least a portionof the top surface of the die 302. This molten, electrically conductivematerial 316 flows so that it electrically connects the top surface ofthe die 302, the electrical coupling 308, the lead 306, a side of thedie 302, the bottom surface of the die 302, the die bond, and/or one ormore surfaces of the lead 302. FIG. 6 additionally depicts electricallyconductive material 318 that has been dispensed over a corner of the topsurface of the die 302. This molten, conductive material flows downward,thereby electrically coupling the top surface of the die 302, one ormore sides of the die 302, the die bond, and/or one or more surfaces ofthe lead 304. All such electrical connections introduce electricalshorts that will be detected during subsequent electrical testing.

FIG. 7 depicts electrically conductive material 320 that has beendispensed over the top surface of the die 302 and over a portion of theelectrical coupling 308. The flow of the material 320 results inelectrical connections between the electrical coupling 308, the lead306, the top surface of the die 302, one or more sides of the die 302, abottom surface of the die 302, the die bond, and/or the lead 304.Electrically conductive material 322 may be dispensed in addition to orin lieu of the electrically conductive material 320. FIG. 8 depictselectrically conductive material 324 that has been dispensed over thetop surface of the die 302. The flow of the material 320 results inelectrical connections between the electrical coupling 308, the lead306, the top surface of the die 302, one or more sides of the die 302, abottom surface of the die 302, the die bond, and/or the lead 304. Thedispensations depicted in FIGS. 6-8 are merely illustrative. The scopeof disclosure includes dispensations of electrically conductive materialof any size, shape and location.

Damage infliction—whether by laser cuts, electrically conductivematerial, or other techniques or materials—may be performed in anysuitable stage of the assembly process. In some embodiments, a lasersource may be coupled to a wire bonding machine (e.g., in proximity tothe bond head area). For example, the laser source may be bolted onto awire bonder to form a linked laser system, and a stage may be providedon an output of the wire bonder to inflict damage on a component if thewire bond detection system determines that the component is defective.Similarly, in some embodiments, a dispenser of electrically conductivematerial may be provided as a bolt-on module for the wire bondingmachine. In some embodiments, a standalone machine separate from thewire bonding machine may be used to inflict damage, whether in the formof laser cuts, the application of electrically conductive material, oranother suitable technique. In some embodiments, a vision system thatincorporates an add-on module for inflicting damage may be used. In suchembodiments, when the vision system detects a defect in the component,the add-on module uses laser cuts, electrically conductive material, orany other suitable technique(s) or material(s) to inflict damage on thedefective component. In general, damage may be inflicted at any timeprior to encapsulation or enclosure of the component.

The scope of disclosure is not limited to intentionally damaging justthe portion(s) of a component that have electrical coupling defects.Instead, a component that is defective in any way may be damaged in anyway so that the component fails a subsequent electrical test in any way.In some embodiments, rather than damaging a die that has a faultyconnection with a single lead, multiple wire bonds coupling the die toanother lead may be severed so that the overall component still failsthe electrical test. In some embodiments, electrically conductivematerial may be deposited between two or more leads, between two or moreelectrical couplings, or some combination thereof to achieve anelectrical short that would fail a subsequent electrical test.

The scope of disclosure is not limited to inflicting damage using lasersor electrically conductive material. As previously explained, anytechnique or material may be used to inflict damage on a defectivecomponent, as long as that technique or material inflicts sufficientdamage so that the component fails an electrical test during theassembly process. Thus, for instance, an electrostatic discharge (e.g.,an electronic flame off (EFO)) may be used to inflict damage onelectrical couplings, such as wire bonds. In some embodiments, ahydrogen flame may be used to melt electrical couplings. In addition,the scope of disclosure is not limited to applying any disclosed orcontemplated materials in any particular manner. Thus, for example, theaforementioned electrically conductive material may be printed insteadof dispensed. In some embodiments, a two-step damaging process may beused in which the top, non-conductive layer of a die is first removedand then an electrically conductive material is applied to create anelectrical short. In some embodiments, electrical parametric defects maybe introduced into the component such that the component fails thesubsequent electrical test. In such embodiments, any suitable techniquemay be used to shift one or more electrical parameters outside of thespecification range. Care should be exercised to shift electricalparameters that are actually tested. For instance, a functional devicewithin a component may be replaced with a non-functional device, or highlevels of heat may be applied to cause catastrophic degradation of oneor more devices within a component. Any and all such techniques andmaterials are contemplated and included within the scope of thisdisclosure.

FIG. 9 is a side view of an integrated circuit package 900. The package900 includes leads 902, a die 904, a die bond 906, a die flag 908,electrical couplings 910, and a mold 912. To function properly, thepackage 900 requires multiple, functional electrical couplings betweenthe die 904 and each of the leads 902. If, during the assembly process,a wire bond detection system or a vision system detects a defect in oneor more electrical couplings, or if it determines that the requiredelectrical couplings are not present in the package 900, the package 900is damaged using, e.g., laser cuts, electrically conductive material,EFO and/or hydrogen flames. FIG. 10 depicts a top-down view of thepackage 900 and shows various non-limiting laser cuts 1000 that could beinflicted on the package 900 to introduce one or more electrical shortsand/or electrical opens. Similarly, FIG. 11 depicts a top-down view ofthe package 900 and shows an illustrative electrically conductivematerial 1002 that could be dispensed on the package 900 to introduceone or more electrical shorts.

FIG. 12 is a flow diagram of a method 1200 for damaging components withdefective or missing electrical couplings. The method 1200 begins byproviding a component having first and second nodes requiring multiple,functional electrical couplings therebetween to operate properly (step1202). As explained above, the component may be a completedsemiconductor package, a multi-die device, a multi-chip module, a systemin package, a passive device, and any such packages, devices, and/ormodules that are in the assembly process. The component may contain anytype and number of nodes (e.g., leads, pins, terminals, different diesurfaces, multiple die), and may require any type and number ofelectrical couplings (e.g., wire bonds, ribbon bonds, clip bonds). Themethod 1200 continues by determining that the component lacks multiple,functional couplings between the first and second nodes (step 1204).This determination may be made using any suitable technique, such as awire bond detection system or a vision system. Other techniques foridentifying defective or insufficient electrical couplings between twoor more nodes are contemplated and encompassed within the scope of thisdisclosure. The method 1200 subsequently comprises inflicting damage onat least part of the component as a result of the determination of step1204 (step 1206). This damage may be inflicted in any number of ways,including the application of electrically conductive material, lasercuts, the application of heat using a technique other than laser,hydrogen flame, EFO, and the like. Other types of damage, such asmechanical damage inflicted by blunt force, are also contemplated. Themethod 1200 finally includes determining, as a result of theintentionally inflicted damage, that the component is defective (step1208). This determination may be made, for instance, during anelectrical test toward the end of the assembly process. If anintentionally-damaged component is identified as defective, it isremoved from the assembly process and discarded or otherwise disposed.The steps of the method 1200 may be modified as desired, including byadding, removing, modifying or rearranging one or more steps.

Numerous other variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations, modifications and equivalents. In addition, the term“or” should be interpreted in an inclusive sense.

What is claimed is:
 1. A method of determining a defective component,the method comprising: providing a component having a first electricalcoupler and a second electrical coupler; determining that the componentlacks a functional electrical coupling between the first electricalcoupler and the second electrical coupler; damaging at least part of thecomponent by shorting the first electrical coupler to the secondelectrical coupler as a result of the determination; and determining, asa result of the damage, that the component is defective.
 2. The methodof claim 1, wherein damaging at least part of the component furthercomprises using a laser to short one or more electrical connections inthe component.
 3. The method of claim 1, wherein damaging at least partof the component further comprises dispensing an electrically conductivematerial to short one or more electrical connections in the component.4. The method of claim 1, wherein damaging at least part of thecomponent further comprises electrically coupling a first surface of adie to a second surface of the die.
 5. The method of claim 1, whereindamaging at least part of the component further comprises electricallycoupling one of a first surface or a second surface of a die to a sidesurface of the die.
 6. The method of claim 1, further comprisingdamaging using a wire bonding machine.
 7. The method of claim 1, whereindetermining that the component is defective further comprisesdetermining that the component is defective using an electrical test. 8.The method of claim 1, wherein the first electrical coupler comprises adie.
 9. The method of claim 1, wherein the second electrical couplercomprises a lead.
 10. A method of determining a defective component, themethod comprising: providing a component having a first electricalcoupler and a second electrical coupler; determining that the componentlacks a functional electrical coupling between the first electricalcoupler and the second electrical coupler; damaging at least part of thecomponent as a result of said determination using a laser to open one ormore electrical connections in the component; and determining, as aresult of the damage, that the component is defective.
 11. The method ofclaim 10, wherein using the laser to open the one or more electricalconnections further comprises opening an electrical coupling between thefirst electrical coupler and the second electrical coupler.
 12. Themethod of claim 11, wherein the electrical coupling between the firstelectrical coupling and the second electrical coupling comprises one ofa wire bond, a clip bond, or a ribbon bond.
 13. The method of claim 10,wherein determining that the component is defective comprisesdetermining that the component is defective during an electrical test.14. The method of claim 10, wherein the first electrical couplercomprises a die.
 15. The method of claim 10, wherein the secondelectrical coupler comprises a lead.
 16. A method of determining adefective component, the method, comprising: providing a componenthaving a first electrical coupler and a second electrical coupler;determining that the component lacks a functional electrical couplingbetween the first electrical coupler and the second electrical coupler;damaging at least part of the component as a result of the determinationusing an electrostatic discharge; and determining, as a result of thedamage, that the component is defective.
 17. The method of claim 16,wherein the component comprises one of an integrated circuit package, adiscrete device package, a multi-die device, a multi-chip module, asystem in package, or a passive device.
 18. The method of claim 16,wherein the component comprises one of a diode or a transistor.
 19. Themethod of claim 16, wherein the first electrical coupler comprises adie.
 20. The method of claim 16, wherein the second electrical couplercomprises a lead.